Mitigating Voltage Saturation in Multi-Source Open-End Winding Induction Motor Systems for Electric Vehicles

This study examines the integration of dual DC sources into an Electric Motor (EM) configured as an Open-End Winding Induction Motor (OEWIM). In this configuration, the motor's neutral point within the rotor cage remains open, enabling power supply from both ends of the stator winding. Each DC source is linked to a three-phase, two-level inverter, which is then connected to the motor. Basically, these dual inverters operate according to an assigned power-sharing coefficient, restricting them to their maximum possible voltage levels. However, if the voltage demand of the motor surpasses the inverter's maximum capacity, voltage saturation occurs, resulting in an inability to fully meet the load demand. Additionally, voltage saturation may also occur during the process of one energy source charging another. To address this challenge, the paper focuses on mitigating voltage saturation by implementing an advanced control algorithm, developed and tested through two distinct methods. Method I works on preserving the previously assigned power-sharing coefficient, ensuring that the input voltage at the motor terminals remains at lower levels to deal with voltage saturation. In contrast, Method II dynamically recalculates the power-sharing coefficient between the sources, enabling a higher input voltage at the motor terminals to satisfy the load demand while effectively preventing voltage saturation. Both methods are experimentally tested and evaluated to demonstrate their effectiveness in addressing voltage saturation within an Open-End Winding Induction Motor (OEWIM) system, controlled using the Field Oriented Control (FOC) technique.